Oscillating wall arrangement for a continuous casting mold

ABSTRACT

Separate wall plates disposed perpendicularly to one another and with a seal between the abutting surfaces of the wall plates, form the mold cavity in a continuous casting mold. Each wall plate has a device for oscillating it in the radial direction of the mold cavity and another device for oscillating it in the plane of its contacting surface with the casting passing through the mold cavity. The wall plates are enclosed by a frame with abutment strips extending between the frame and the outer surface of the plates. Further, elastic elements are articulated to and extend between the wall plates and the frame. The elastic elements are adjustable for adapting to the tapering action of the casting as it moves through the mold.

tlnited States Patent [191 Voss [45] Feb. 26, 1974 1 OSCILLATING WALLARRANGEMENT FOR A CONTINUOUS CASTING MOLD [73] Assignee: Demag AG,Duisburg, Germany [22] Filed: June 1, 1971 [21] Appl. No.: 148,631

[52] US. Cl 164/260, 164/73, 164/281 [51] Int. Cl B22d 27/08 [58] Field01 Search 164/73, 83, 260, 261, 281

[56] References Cited UNITED STATES PATENTS 3,667,534 6/1972 Kanokogi etal 164/260 X 3,075,264 1/1963 Wognum 164/260 X 3,307,230 3/1967 GOSS164/281 3,565,158 2/1971 Ciochetto 164/83 X 3,467,168 9/1969 Charman164/83 X 3,455,370 7/1969 Easton et al. 164/260 X 3,613,771 10/1971Bieri 164/261 X FOREIGN PATENTS OR APPLICATIONS 695,752 10/1964 Canada164/281 Primary Examiner-J. Spencer Overholser Assistant Examiner-JohnE. Roethel Attorney, Agent, or Firm-Toren & McGeady [5 7] ABSTRACTSeparate wall plates disposed perpendicularly to one another and with aseal between the abutting surfaces of the wall plates, form the moldcavity in a continuous casting mold. Each wall plate has a device foroscillating it in the radial direction of the mold cavity and anotherdevice for oscillating it in the plane of its contacting surface withthe casting passing through the mold cavity. The wall plates areenclosed by a frame with abutment strips extending between the frame andthe outer surface of the plates. Further, elastic elements arearticulated to and extend between the wall plates and the frame. Theelastic elements are adjustable for adapting to the tapering action ofthe casting as it moves through the mold.

11 Claims, 4 Drawing Figures PATENTEB FEB 26 M4 lnventor;

WILHELN V055 SUMMARY OF THE INVENTION The present invention is directedto the arrangement of a continuous casting mold for metal, andespecially for steel, and, more particularly, it concerns separate wallmembers assembled together to form a mold cavity and with meansassociated with the wall members for oscillating them in two differentdirections.

In the past casting molds having walls oscillatable in two directionshave only been feasible for casting copper. Other metallic materials,and in particular steel, whose thermal conductivity is lower than coppercould not be east in such molds. Because of its high conductivity,copper as the melt in a continuous casting arrangement causes lessdifficulty than does steel. In the prior art it has been realized thatindependently oscillatable walls disadvantageously limit the coolingrate because the walls defining the mold cavity do not remain inuninterrupted contact with the continuous casting. In an attempt tosolve the problem, the amplitude of the vibrations or oscillations hasbeen decreased from top to bottom in a vertically arranged mold. In suchan arrangement the mold halves are pivotally mounted at their lower endson horizontal shafts. In this known arrangement the mold surfaces pivotperpendicularly to the continuous casting and, while offering someimprovement, the casting formed in such a device have not beencompletely free from cracks. It has been found that a sliding actionoccurs between the mold and the continuous casting which causes tensilestresses in the casting.

Further, when the mold surfaces pivot perpendicularly to the casting,the casting is exposed to relatively hard blows from the surfaces of themold and such blows may easily develop surface defects in the castings.

Accordingly, it has been proposed to oscillate the mold surfaces in acircular or other closed orbit so that the surfaces move in the castingdirection in contact with the casting and then become separated from thecasting and return in the direction opposite to the casting direction tocomplete the orbit before returning into contact with the casting. As aresult, the casting is contacted by the surfaces of the mold only whilethe surfaces are moving in the same direction as the casting.

However, because of the liquid characteristic of the material being castas it enters into the mold cavity the manner of effecting this orbitalmovement of the mold surfaces is difficult without disadvantageouslyeffecting the portion of the casting which is in the liquid state.

In one known device two bisected, matching mold parts which form themold cavity are secured by means of bearings on eccentrically arrangedshafts. As the shafts rotate a continual back-and-forth motion isimparted to the mold perpendicular to the casting direction.

When the above-mentioned device was used for continuously casting steelit was found impractical because it was incapable of removing the higherheat content of the steel in a sufficiently rapid manner. Since the moldsurfaces are moved away from the surfaces of the casting during eachradial movement of the mold, a time interval exists during each cyclewhen no heat is being extracted from the casting.

When the continuous casting mold is oscillated in the casting direction,the heat transfer is suitable for a greater quantity of heat per unit oftime. However, in

such as arrangement the shell of the casting is stressed due to theoscillating action and surface defects occur at periodic intervals oftime, for example, due to the velocity of the oscillating movementdefects may form on the surface of the casting which make it unsuitablefor further processing. In vertical casting arrangement, depending onwhether the mean mold velocity downward is greater or less than thecasting velocity, the move ment is termed negative strip or positivestrip. It is possible for the upward and downward movement of the moldto take place at uniform speeds or the upward movement can be at agreater speed than the downward movement or vice versa. To provide sucha movement in a specific case requires considerable expense in equipmentto produce the exact movement of the mold in the casting direction,since not only the mold but the mold table must also be moved upwardlyand downwardly. Moreover, in the case of curved continuous castingmolds, the accuracy of the movement and the design of the requireddevice is still more complicated than for vertically arranged molds dueto the arcuate character of the movement. In curved mold arrangements awearing action takes place on the mold walls due to the relativemovement between the casting and the mold surfaces.

Therefore, in view of the problems involved in continuous castingarrangements where the wall surfaces of the mold perform a radialmovement, it is the primary object of the present invention to provide amold construction which overcomes the previously experienced problemsand one that can be used for metals other than copper, and in particularfor the casting of various types of steel. By means of the presentinvention, a better heat transfer is provided between the mold surfacesand the casting, so that metals of extremely high heat content can forman adequate casting shell and easily separate from the mold surfaces.

Therefore, in accordance with the present invention, separate wallplates are arranged for forming the mold cavity in a continuous castingmold and the wall plates are arranged for additional oscillatingmovement in the plane of the surface of contact between the wall platesand the casting within the mold cavity. With the combination of theoscillatory movement proposed by the invention and the conventionalradially directed oscillatory movement, it is possible to effect theseparation of the casting shell from the wall plates forming the moldcavity at a cost of energy and material which is as low as possible, andalso to support the casting shell while avoiding the development of anytensile stresses. Furthermore, improved heat transfer is possible bymeans of the laterally directed displacements of the wall plates, sothat the previously employed radially directed oscillatory movement isnecessary only to insure better mixing of the liquid components withinthe casting and this feature also affords an acceleration of the heatremoval from the interior or core of the casting into its outer zones.The different oscillatory movements of the wall plates thus cause soundor ultrasound waves to impinge upon the contents within the mold cavity,that is acting upon the internal structure of the casting and at thesame time promoting the separation of the casting shell from theabutting surfaces of the wall plates.

Additional features can be incorporated into the casting mold assemblyfor improving its operation in accordance with the present invention.The individual wall plates are positioned inwardly from an enclosing andlongitudinally extending frame and adjustable abutment strips extendbetween the frame and the wall plates providing support for the wallplates. These abutment strips or spacers and also the wall plates areexchangeable, so that the cross section of the mold cavity can be variedat a relatively small cost. Accordingly, the frame enclosing theexterior of the casting mold assembly acts as the basis for a system ofexchangeable parts with the formation of variable cross-sections for themold cavity based on the cross-sectional area provided within the frame.

Another feature of the invention is the provision of at least one devicefor generating oscillations being associated with each of the wallplates, such a device can be driven magnetically or by an electricmotor. With this arrangement a much simpler oscillating means isprovided, since lever elements and a plurality of bearing points are nolonger needed. The alignment of such lever elements and bearing pointshas caused difficulty in previous oscillating devices and their use wasconsidered to be disadvantageous because of the wear which developed andthe generally heavy burden they imposed on the casting plant. Anotherfeature of the present arrangement which is especially favorable is thesynchronous operation of the oscillating devices for the pairs ofoppositely arranged wall plates. By synchronizing the oscillations ofthe wall plates it is possible to maintain the necessary support for thecasting shell as it moves through the mold cavity. By synchronizingopposed pairs of plates the oscillations in one direction for a pair ofwall plates can be staggered with the oscillations of another pair ofwall plates.

Still another feature of the invention which greatly facilitates theoscillatory action, is the use of elastic elements for supporting theindividual wall plates on the frame. By employing adjustable elasticelements the disposition of the wall plates can be accommodated to theinwardly tapering action of the solidifying casting as it moves throughthe mold cavity. Because of the construction of the mold, butt jointsare formed between the separate wall plates through which molten castingmetal could flow under unfavorable conditions, however, since even aburr or similar defect on the surface of the casting is undesirable, itis important to arrange the abutting portions of the wall plates with apacking strip exposed to the pressure of a heat-resistant lubricanttherebetween to afford the desired seal for the joint. In this way thelubricant fills any gap or space formed between the abutting portions.The lubricant reduces the friction between the abutting walls plates ofthe mold and also between the casting and the surfaces of the moldduring the oscillatory movement of the mold parts, the lubricant entersthe mold cavity only when a space occurs within the cavity. Since thepacking strip is under pressure from the lubricant, it prevents thelubricant from flowing outwardly from the joint between the wall plates.Accordingly, the problem of providing a seal between the wall plates isovercome in an extremely simple manner.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a plan view of a continuous casting mold assembly constructedin accordance with the present invention;

FIG. 2 is a vertical axial section taken along the line AA in FIG. 1;

FIG. 3 is a partial vertical section similar to FIG. 2, however, viewedfrom the side in relation to FIG. 2; and

FIG. 4 is an enlarged, partial, horizontal sectional view of the buttjoint between two adjacent wall plates of the continuous casting mold asindicated in FIG. 2, and viewed downwardly as in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1, a continuous castingmold assembly is shown with the mold cavity 1 formed by four wall plates2, so that the mold cavity has a square transverse cross section. Thewall plates 2 extend perpendicularly to one another with one end edge ofeach plate being in contact with the face surface of another plate andits opposite end edge extending outwardly from the free surface of theoppositely disposed wall plate. The metal being cast is chargeddownwardly into the mold cavity 1 with the casting being formed as itpasses downwardly through the mold. Due to the pressure exerted by thecasting metal against the wall plates 2, they are forced outwardlyagainst abutment strips or members 3 which are located at the upper andlower ends of the plates and extend in planes transverse to the verticalaxis of the mold cavity. Encircling the wall plates 2 and the abutmentstrips 3 is a closed frame 4 which extends in the longitudinal directionof the mold cavity for the height of the wall plates. Based on thedesired cross sectional area of the mold cavity 1, the abutment strips 3have special shapes or dimensions for providing the desired dimensionsfor the mold cavity 1. For effecting the radially directed oscillatorymovement of the wall plates, they are supported on their outer surfacesby elastic elements 5 which extend outwardly and are secured in anarticulated manner to the frame 4. As indicated in the drawing, twopairs of elastic elements 5 support the wall plates 2 from the frame 4,however, a greater number of such elastic elements can be used dependingon the conditions involved. Such elastic elements 5 may be formed ofSCHWING-METALLEN (registered trademark), that is oscillating metals,spring packages or compressed air cylinders and as such provideassemblies which are quickly installable and removable.

By means of the elastic elements 5, the wall plates 2 can be adjusted toaccommodate the tapered configuration of the solidifying casting as itpasses downwardly through the mold cavity. Alternatively, the elasticelements may be constructed so that they adapt automatically to thetapered configuration of the casting. As indicated in FIGS. 1 and 2,each of the wall plates 2 acts as a carrier or support for oscillationdevice 6 and the wall plate forms a unit with the device. As theoscillating device 6, an energy transmitter may be used which releases asound wave into the material being cast so that its crystallization,during the solidifying action, can be favorably influenced.

Additionally, the oscillating devices 6 also serve for the equalizationof the oscillating movements which are brought about by the essentialcomponent of the continuous casting mold in accordance with theinvention. Further, as distinguished from devices used in the past,additional oscillating devices 7 are provided extending between onevertically extending edge of the wall plates 2 and the oppositelydisposed surface of the frame 4. As indicated in the drawing, theoscillating devices 7 incorporate elastic elements so that a minimum ofenergy is expanded in effecting the movement of the wall plates inplanes perpendicular to one another, that is, in the planes of theirsurface in contact with the shell of the casting passing through themold cavity. The present invention is directed especially to thecombined oscillatory movements provided by the devices 6 and 7 so thateach wall'plate'has, in combination, a radially directed oscillatingmovement and another oscillating movement in the direction of thesurface or interface 8 between the casting shell and the contacting faceof the wall plates 2. By oscillating the surface of the wall platesrelative to the outer surface of the casting shell, the desired supportfor the casting surface is maintained.

As indicated in FIG. 2, the lower ends of the wall plates 2 are mountedon rolls 9 for supporting the weight of the mold. Further, as indicatedabove, and as shown in FIG. 2, the elastic elements 5 are articulated attheir points of attachment 10 to the wall plates 2 and at their pointsof attachmentll to the frame 4 for affording the relative displacementwhich occurs during the oscillatory movement the wall plates.

In FIG. 4, the joint between a pair of wall plates is indicated with agroove formed in the edge of the wall plate which contacts the surfaceof the adjacent wall plate. A lubricant conduit 12 extends through thegroove and is connected to a pressure reservoir, not shown. Within thegroove, in the part spaced outwardly from the mold cavity 1, a packingstrip is arranged so that it is forced into contact with the face 14 bythe heat-resistant lubricant supplied into the groove through theconduit 12. By means of the heat-resistant lubricant and the packingstrip 13, a seal is provided between the abutting surfaces of the wallplates 2 and, further, a lubricating action is provided between the wallplates and between the joint and the edge of the casting or strandmoving through the mold cavity ll. Concerning this disclosure, referenceis made to Handbuch des Stranggiessens (Manual of Continuous Casting),Hermann, pp 135-137.

I claim ll. Continuous casting mold assembly for metals and particularlyfor steel, comprising a plurality of mold plates angularly disposedrelative to one another and forming a longitudinally extending laterallyclosed mold cavity, first means connected to said mold plates foroscillating each said mold plate in the radial direction of the moldcavity, second means connected to each said mold plate at a locationspaced from the connection of said first means thereto for oscillatingeach said mold plate in the plane 'of its surface within the moldcavity, each of said moldplates having one longitudinally extending edgein abutment with the surface of another said wall plate which lines themold cavity, said abutting edge having a groove formed therein extendingin the longitudinal direction of the mold cavity, the groove beingspaced outwardly from the surface of said wall plate defining the moldcavity, a packing strip positioned within and extending in alongitudinal direction of the groove, and means for applying apressurized heat-resistant lubricant into the groove for forcing saidpacking strip in sealing action between the abutting said mold platesfor preventing any outward flow of the molten metal within the moldcavity.

2. Continuous casting mold assembly, as set forth in claim 1,characterized therein by a frame laterally enclosing and spacedoutwardly from said mold plates, said frame extending in thelongitudinal direction of the mold cavity, adjustable abutment stripsextending transversely of the longitudinal direction of the mold cavityand extending between said mold plates and said frame.

3. Continuous casting mold assembly, as set forth in claim ll,characterized in that said second means for oscillating each said moldplate comprises an oscillating device in contact with one longitudinallyextending edge of each said mold plate.

4. Continuous casting mold assembly, as set forth in claim 2,characterized in that a plurality of elastic elements are associatedwith each said mold plate and said elastic elements extend transverselyof the longitudinal direction of the mold cavity and are connected toand extend between said frame and said mold plates.

5. Continuous casting mold assembly, as set forth in claim 4,characterized in that said elastic elements are articulated to said moldplates and said frame.

6. Continuous casting mold assembly, as set forth in claim 4,characterized in that said elastic elements are adjustable in lengthrelative to their position in the longitudinal direction of the moldcavity for adapting to the tapering configuration of the casting as itsolidifies while passing through the mold cavity.

7. Continuous casting mold assembly, as set forth in claim 1,characterized in that rolls are mounted at the lower ends of each ofsaid mold plates for supporting said mold plates.

8. Continuous casting mold assembly, as set forth in claim 1,characterized in that said mold plates are disposed perpendicularly toone another forming a rectangular cross-section for the mold cavitytransversely of the longitudinal direction thereof.

9. Continuous casting mold assembly, as set forth in claim 1,characterized in that said first means for oscillating said mold platescomprises an oscillating generator mounted on each of said mold platesin spaced relationship from the edges thereof.

10. Continuous casting mold assembly, as set forth in claim 1,characterized in that said first means for oscillating said mold platescomprises an oscillating device connected to the exterior surface ofeach said mold plate in spaced relationship from the edges thereof foroscillating said mold plates in the radial direction of the mold cavity.

11. Continuous casting mold assembly, as set forth in claim 8,characterized in that each said mold plate extends between twooppositely spaced said mold plates and has one edge extending in thelongitudinal direction of the mold cavity in contact with the surface ofone of the oppositely spaced said mold plates which defines the moldcavity and with its other edge extending in the longitudinal directionof the mold cavity extending outwardly from the surface of the other oneof said oppositely spaced said mold plates which forms the oppositesurface of the mold cavity, and said second means for oscillating saidmold plates connected to the other edge of each said mold plate.

i i *l

1. Continuous casting mold assembly for metals and particularly forsteel, comprising a plurality of mold plates angularly disposed relativeto one another and forming a longitudinally extending laterally closedmold cavity, first means connected to said mold plates for oscillatingeach said mold plate in the radial direction of the mold cavity, secondmeans connected to each said mold plate at a location spaced from theconnection of said first means thereto for oscillating each said moldplate in the plane of its surface within the mold cavity, each of saidmold plates having one longitudinally extending edge in abutment withthe surface of another said wall plate which lines the mold cavity, saidabutting edge having a groove formed therein extending in thelongitudinal direction of the mold cavity, the groove being spacedoutwardly from the surface of said wall plate defining the mold cavity,a packing strip positioned within and extending in a longitudinaldirection of the groove, and means for applying a pressurizedheat-resistant lubricant into the groove for forcing said packing stripin sealing action between the abutting said mold plates for preventingany outward flow of the molten metal within the mold cavity. 2.Continuous casting mold assembly, as set forth in claim 1, characterizedtherein by a frame laterally enclosing and spaced outwardly from saidmold plates, said frame extending in the longitudinal direction of themold cavity, adjustable abutment strips extending transversely of thelongitudinal direction of the mold cavity and extending between saidmold plates and said frame.
 3. Continuous casting mold assembly, as setforth in claim 1, characterized in that said second means foroscillating each said mold plate comprises an oscillating device incontact with one longitudinally extending edge of each said mold plate.4. Continuous casting mold assembly, as set forth in claim 2,characterized in that a plurality of elastic elements are associatedwith each said mold plate and said elastic elements extend transverselyof the longitudinal direction of the mold cavity and are connected Toand extend between said frame and said mold plates.
 5. Continuouscasting mold assembly, as set forth in claim 4, characterized in thatsaid elastic elements are articulated to said mold plates and saidframe.
 6. Continuous casting mold assembly, as set forth in claim 4,characterized in that said elastic elements are adjustable in lengthrelative to their position in the longitudinal direction of the moldcavity for adapting to the tapering configuration of the casting as itsolidifies while passing through the mold cavity.
 7. Continuous castingmold assembly, as set forth in claim 1, characterized in that rolls aremounted at the lower ends of each of said mold plates for supportingsaid mold plates.
 8. Continuous casting mold assembly, as set forth inclaim 1, characterized in that said mold plates are disposedperpendicularly to one another forming a rectangular cross-section forthe mold cavity transversely of the longitudinal direction thereof. 9.Continuous casting mold assembly, as set forth in claim 1, characterizedin that said first means for oscillating said mold plates comprises anoscillating generator mounted on each of said mold plates in spacedrelationship from the edges thereof.
 10. Continuous casting moldassembly, as set forth in claim 1, characterized in that said firstmeans for oscillating said mold plates comprises an oscillating deviceconnected to the exterior surface of each said mold plate in spacedrelationship from the edges thereof for oscillating said mold plates inthe radial direction of the mold cavity.
 11. Continuous casting moldassembly, as set forth in claim 8, characterized in that each said moldplate extends between two oppositely spaced said mold plates and has oneedge extending in the longitudinal direction of the mold cavity incontact with the surface of one of the oppositely spaced said moldplates which defines the mold cavity and with its other edge extendingin the longitudinal direction of the mold cavity extending outwardlyfrom the surface of the other one of said oppositely spaced said moldplates which forms the opposite surface of the mold cavity, and saidsecond means for oscillating said mold plates connected to the otheredge of each said mold plate.